Добавил:
ivanov666
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Обучение чтению литературы на английском языке для студентов, обучающихся по направлению подготовки 27.03.04 - Управление в технических системах. Учеб
.pdf
a computer system. These instructions are loaded into RAM every time you
start your computer, and they remain there until you turn off your computer.
People sometimes tend to confuse RAM and hard-disk storage, maybe
because both components hold data, because they typically are “hidden”
inside the system unit, or because they can both be measured in gigabytes.
To differentiate between RAM and hard-disk storage, remember that RAM
holds data in circuitry that’s directly connected to the system board,
whereas hard-disk storage places data on magnetic media. RAM is
temporary storage; hard-disk storage is more permanent. Besides, RAM
usually has less storage capacity than hard-disk storage.
In RAM, microscopic electronic parts, called capacitors hold the bits
that represent data. You can visualize the capacitors as microscopic lights
that can be turned on and off. A charged capacitor is “turned on” and
represents a”1” bit. A discharged capacitor is “turned off” and represents a
“0” bit. Each bank of capacitors holds eight bits – one byte of data. A RAM
address on each bank helps the computer locate data as needed, for
processing.
Each RAM location has an address and uses eight capacitors to hold the
eight bits that represent a byte.
In some respects, RAM is similar to a chalkboard. You can use a
chalkboard to write mathematical formulas, erase them, and then write an
outline for a report. RAM contents can be changed just by changing the
charge of the capacitors. Unlike disk storage, most RAM is volatile, which
means it requires electrical power to hold data. If the computer is turned off
or the power goes out, all data stored in RAM instantly and permanently
disappears.
Today’s personal computer operating systems are quite adept at
allocation RAM space to multiple programs. If a program exceeds its
allocated space, the operating system uses an area of the hard disk, called
virtual memory, to store parts of programs or data files until they are
needed. By selectively exchanging the data in RAM with the data in virtual
memory, your computer effectively gains almost unlimited memory
capacity.
RAM components vary in speed, technology, and configuration. RAM
speed is often expressed in nanoseconds or megahertz. One nanosecond
(ns) is 1 billionth of a second. RAM speed can also be expressed in MHz
(millions of cycles per second). Most of today’s personal computers use
SDRAM (synchronous dynamic RAM), fast and relatively inexpensive, it
is typically available on a small circuit board called a DIMM (dual inline
memory module) or RDRAM (Rambus dynamic RAM), first developed
for a game system and then adapted for use in personal computers.
Read-Only Memory
ROM (read-only memory) is a type of memory circuitry that holds the
computer’s startup routine. Whereas RAM is temporary and volatile, ROM
is permanent and non-volatile. ROM circuitry holds “hard-wired”
instructions that are a permanent part of the circuitry and remain in place
even when the computer power is turned off.
When you turn on your computer, the microprocessor receives electrical
power and is ready to begin executing instructions. As a result of the power
being off, however, RAM is empty and doesn’t contain any instructions for
the microprocessor to execute. Now ROM plays its part. ROM contains a
small set of instruction called the ROM BIOS (basic input/output
system).These instructions tell the computer how to access the hard disk,
find the operating system, and load it into RAM. After the operating system
is loaded, the computer can understand your input, display output, run
software, and access your data.
CMOS Memory
To operate correctly, a computer must have some basic information
about storage, memory, and display configurations. The information is held
in CMOS (pronounced “SEE moss”), a type of chip that requires very little
power to hold data. It can be powered by a small battery that is integrated
into the system board and automatically recharges while your computer
power is on. The battery trickles power to the CMOS chip so that it can
retain vital data about your computer system configuration even when your
computer is turned off. When you change the configuration of your
computer system, the data in CMOS must be updated.
The more data and programs that can fit into RAM, the less time your
computer will spend moving data to and from virtual memory.
Exercises:
1. Fill in the blanks choosing from the variants given.
1. CMOS memory is a type of chip that requires very little power to …
data.
a) affect b) compare
c) hold d) execute
2. As a result of the power being off RAM does not … any instructions
for the microprocessor to execute.
a) contain b) allocate
c) develop d) provide
3. The ALU uses registers to hold data as the microprocessor …
arithmetic and logical operations.
a) gains b) compares
c) performs d) exchanges
4. When the microprocessor receives electrical power, it is ready to
begin … instructions.
a) executing b) exchanging
c) allocating d) holding
5. Microprocessor instruction sets can be classified as … or … .
a) RAM or ROM b) CISC or RISC
c) ROM BIOS d) CMOS memory
6. The instructions for loading the operating system into RAM when a
computer is first turned on are stored in … memory.
a) RAM b) CMOS
c) RISC d) ROM
7. A microprocessor (sometimes simply referred to as a “processor”) is
an integrated circuit … to process instructions.
a) affected b) performed
c) held d) designed
2. Fill in the gaps in the text.
The microprocessor and memory are two of the most important
components in a computer. The microprocessor is an integrated circuit,
which is ___ to process data based on a set of instructions. The
microprocessor’s ALU ___ arithmetic and logical operations. The control
unit fetches each instruction, ___ it, loads data into the ALU registers, and
directs all the processing activities within the microprocessor.
Microprocessor performance is measured in ___ – the number of cycles per
second, or clock rate. Other factors ___ overall processing speed include
word size cache size, instruction set complexity, and ___.
3. Answer the following questions.
1. What exactly is a microprocessor? How does it work?
2. Where does the microprocessor get its instructions?
3. What impact does word size have on performance?
4. How does the cache size affect performance?
5. How does the instruction set affect performance?
6. What is the difference between serial processing and parallel
processing?
7. How is it possible to compare microprocessor performance?
8. How does RAM differ from hard-disk storage?
9. If a computer has RAM, why does it need ROM?
10. Where does a computer store its basic hardware settings?
UNIT 5
Read and translate the text
INPUT AND OUTPUT DEVICES
Basic Input Devices
Most computer systems include a keyboard and pointing device, such as
a mouse, for basic data input. Additional input devices, such as scanners,
digital cameras, and graphics tablets, are handy for working with graphical
input. Microphones and electronic instruments provide input capabilities for
sound and music. A keyboard allows the user to key in programs and data
and to control the computer system. Letters, numbers, symbols and blank
spaces are known as characters. The design of most computer keyboards is
based on the typewriter’s QWERTY layout (because these are the first six
letters on the top left of the keyboard), which was engineered to keep the
typewriter’s mechanical keys from jamming. In addition to the basic typing
keypad, computer keyboards include a collection of function keys designed
for computer-specific tasks, a calculator-style numeric keypad, and an
editing keypad with keys such as End, Home, and Page Up.
A pointing device allows you to manipulate an on-screen pointer and
other screen-based graphical controls. The most popular pointing devices
for personal computers include mice, trackballs, pointing sticks, trackpads,
and joysticks. A standard desktop computer includes a mouse as its primary
pointing device. A mouse includes one or more buttons that can be
“clicked” to input command selections. To track its position, a computer
mouse uses one of two technologies: mechanical or optical. A mechanical
mouse reads its position based on the movement of a ball that rolls over a
mouse pad placed on a desk. An optical mouse uses an onboard chip to
track a light beam as it bounces off a surface, such as a desk, clipboard, or
mouse pad. An optical mouse provides more precise tracking, greater
durability, less maintenance, and more flexibility to use the mouse on a
wide variety of surfaces without a mouse pad. A pointing stick, looks like
the top of an eraser embedded in the keyboard of a notebook computer. A
trackpad is a touch-sensitive surface on which you can slide your fingers to
move the on-screen pointer. A trackball looks like a mechanical mouse
turned upside down. A joystick looks like a small version of a car’s stick
shift and is used mostly for playing games.
Display Devices
A computer display screen is usually classified as an output device
because it typically shows the results of a processing task. Some screens,
however, can be classified as both input and output device because they
include touch-sensitive technology that accepts input. Display devices used
for output offer three technology options: CRT, LCD, and plasma. Gun-like
mechanisms in the CRT (cathode ray tube) spray beams of electrons
toward the screen and activate individual dots of color that form an image.
CRT display devices often simply called “monitors”, are bulky, however,
and consume a fair amount of power. An LCD (liquid crystal display)
produces an image by manipulating light within a layer of liquid crystal
cells. Modern LCD technology is compact in size and lightweight, and
provides an easy-to-read display. The advantages of LCD monitors (or “flat
panel displays”) include display clarity, low radiation emission, portability,
and compactness. Plasma screen technology creates an on-screen image by
illuminating miniature colored fluorescent light arrayed in a panel-like
screen. The name “plasma” comes from the type of gas that fills fluorescent
lights and gives them their luminescence. Like LCD screens, plasma screens
are compact, lightweight, and more expensive than CRT monitors. They are
rather energy consuming, too.
Image quality is a factor of screen size, dot pitch, width of viewing
angle, refresh rate, resolution, and color depth. Screen size is the
measurement in inches from one corner of the screen diagonally across to
the opposite corner. The quality of a screen is often measured by the number
of horizontal and vertical pixels used to create it. A pixel is a dot of color on a
photo image or a point of light on a display screen. It can be in one of two
modes: “on” or “off”. A larger number of pixels per square inch means a
higher resolution, or clarity and sharpness of the image. The distance
between one pixel on the screen and the next nearest pixel is known as dot
pitch. Dot pitch (dp) is a measure of image clarity. A smaller dot pitch
means a clearer image. Greater pixel densities and smaller dot pitches yield
sharper images of higher resolution. A monitor’s viewing angle width
indicates how far to the side you can still clearly see the screen image. A
wide viewing angle indicates that you can view the screen from various
positions without compromising image quality. CRT and plasma screens
offer the widest viewing angles. A CRT’s refresh rate (also referred to as
“vertical scan rate”) is the speed at which the screen is repainted. The faster
the refresh rate, the less the screen flickers. Refresh rate is measured in
cycles per second, or Hertz (Hz). The number of colors a monitor can
display is referred to as color depth or “bit depth”. Most PC display devices
have the capability to display millions of colors. The number of horizontal
and vertical pixels that a device displays on a screen is referred to as its
resolution. The resolution for many early PC displays was referred to as
VGA (Video Graphics Array). Higher resolutions were later provided by
SVGA (SuperVGA), XGA (eXtended Graphics Array), SXGA (Super
XGA), and UXGA (Ultra XGA).
Printers
Printers are one of the most popular output devices, they usually use ink
jet or laser technology. An ink jet printer has a nozzle-like print head that
sprays ink onto paper to form characters and graphics. A laser printer uses
the same technology as a photocopier to paint dots of light on a lightsensitive drum. Laser technology is more complex than ink jet technology,
which accounts for the higher price of laser printers. A recurring cost of
using a printer is the ink-jet or laser cartridge that must be replaced
every few thousand pages of output. Printers differ in resolution, speed,
duty cycle, operating costs, duplex capability, and memory. Printer
resolution – the density of the gridwork of dots that create an image – is
measured by the number of dots printed per linear inch, abbreviated as dpi,
normally 900 dpi is enough. Printer speeds are measured either by pages
per minute (ppm) or character per second (cps). A printer’s duty cycle
determines how many pages a printer is able to process, usually measured
per month (ppm). A printer with duplex capability can print on both sides
of the paper, though it will slow down the print process. A computer sends
data for a printout to the printer along with a set of instructions on how to
print that data. Printer Control Language (PCL) is the most widely used
language for communication between computers and printers, but
PostScript is an alternative printer language that many publishing
professionals prefer. The data that arrives at a printer along with its printer
language instructions requires memory.
Installing Peripheral Devices
Today, many peripheral devices connect to an external USB (universal
serial bus) port and Windows automatically loads their service drivers,
making installation as simple as plugging in a table lamp. USB is currently
the most popular technology for connecting peripherals.
USB ports are conveniently located on the front of the system unit for
easy access. When you install a peripheral device, you are creating a
connection for data to flow between the device and the computer. Within a
computer, data travels from one component to another over circuits called a
data bus. One part of the data bus runs between RAM and the
microprocessor. Other parts of the data bus connect RAM to various storage
and peripheral devices. The segment of the data bus that extends between
RAM and peripheral devices is called the expansion bus. As data moves
along the expansion bus, it can travel through expansion slots, cards,
ports, and cables. An expansion slot is a long, narrow socket on the system
board into which you can plug an expansion card. An expansion card is a
small circuit board that gives a computer the capability to control a storage
device, an input device, or an output device. Expansion cards are also called
“expansion boards”, “controller cards”, or “adapters”. Expansion cards are
built for only one type of slot. An expansion port is any connector that
passes data in and out of a computer or peripheral device. Built in ports
supplied with a computer usually include a mouse port, keyboard port,
serial port, and USB ports. Most notebook computers are equipped with
several USB ports.
Some devices require software, called a device driver, to set up
communication between your computer and the device. The directions
supplied with your peripheral device include instructions on how to install
the device driver. Typically, you use the device driver disk or CD one time
to get everything set up, and then you can put the disk away in a safe place.
Installing a peripheral device you should remember that the cable you use
must match the peripheral device and a port on the computer. If the right
type of port is not available, you might have to add an expansion card. Once
the connection is made, PnP should recognize the new device. If not, you
will probably have to install driver software.
Exercises:
1. Match the meaning of the following English words with their
Russian equivalents.
1. storage a) жесткий диск
2. medium b) резервирование; резервная
копия
3. read-write head c) темное, неотражающее пятно
на поверхности CD-ROM
4. pit d) отражающее пятно на
поверхности CD-ROM
5. solid state storage e) универсальная головка
считывания – записи
6. land f) авария (плавающих) головок
7. platter g) контроллер, устройство
управления
8. head crash h) запоминающее устройство
на монолитном носителе
9. backup i) память, запоминающее
устройство
10. controller j) носитель; средство
2. Match the beginnings of the sentences with the endings.
1. In addition to the basic typing keypad, computer keyboards include a
collection of function keys
2. A pointing device allows you
3. A recurring cost of using a printer is the ink-jet or laser cartridge.
4. An optical mouse provides more precise tracking, less maintenance,
and more flexibility
5. As data moves along the expansion bus,
6. A CRT (cathode ray tube) display is a device
a) it can travel through expansion slots, cards, ports, and cables
b) to use the mouse on a wide variety of surfaces without a mouse pad
c) designed for computer-specific tasks.
d) to manipulate an on-screen pointer and other screen-based graphical
controls
e) that offers an inexpensive and dependable way of output.
f) that must be replaced every few thousand pages of output.
3. Fill in the missing words choosing from the variants given.
a) viewing angle b) pixel c) resolution d) surface
e) allows f) pitches g) display
1. A keyboard … the user to key in programs and data and to control the
computer system.
2. An optical mouse uses an onboard chip to track a light beam as it
bounces off a …, such as a desk, clipboard, or mouse pad.
3. Some … screens, can be classified as both input and output devices.
4. Greater … densities and smaller dot … yield sharper images of higher
resolution.
5. A wide … indicates that you can view the screen from various
positions without compromising image quality.
6. Printer … is measured by the number of dots printed per linear inch.
4. Fill in the gaps in the text with appropriate words.
Most computer systems include a keyboard and some type of ___ device
for basic data input. A mouse is standard equipment with most desktop
computer systems. For output, most computers include a display device. A
___ produces an image by spraying electrons toward the screen. ___
technology produces an image by manipulating light within a layer of liquid
crystal cells. ___ screen technology creates an on-screen image by
illuminating miniature fluorescent lights arrayed in a panel-like screen.
Image quality for a display device is a factor of screen size, ___ ___, ___ of
viewing angle, resolution, refresh rate, and color ___.
5. Answer the following questions.
1. What devices are used to get data into a computer?
2. What does a pointing device do?
3. What options are for output devices?
4. Which display technology produces the best image?
5. What printer technologies are most popular with personal computer
users?
6. What are the operating characteristics of a printer?
7. How does a computer move data to and from peripheral devices?
8. What is an expansion slot? What is an expansion card used for?
9. What is an expansion port? What are other names for it?
10. Why do some peripheral devices include a disk or CD?
UNIT 6
Read and translate the text
DATA BACKUP
Backup and restore procedures
Have you ever mistakenly copied an old version of a document over a
new version? Has your computer's hard disk drive gone on the fritz? Did a
virus wipe out your files? Has lightning “fried” your computer system?
These kinds of data disasters are not rare; they happen to everyone. You
can’t always prevent them, so you need a backup plan that helps you
recover data that's been wiped out by operator error, viruses, or hardware
failures.
A backup is a copy of one or more files that has been made in case the
original files become damaged. A backup is usually stored on a different
storage medium from the original files. For example, you can back up files
from your hard disk to a different hard disk, a writable CD or DVD: tape,
floppy disk, or Web site.
A good backup plan allows you to restore your computing environment
to its pre-disaster state with a minimum of fuss. Unfortunately, no single
backup plan fits everyone’s computing style or budget. You must devise
your own backup plan that’s tailored to your particular computing needs.
A full-system backup contains a copy of every program, data, and
system file on a computer. The advantage of a full-system backup is that
you can easily restore your computer to its pre-disaster state simply by
copying the backup files to a new hard disk. A full-system backup takes a
lot of time, however, and automating the process requires a large-capacity
tape backup device or a second hard disk drive.
A workable alternative to a full system backup is a “selective” backup
that contains only your most important data files. The disadvantage of this
backup strategy is that because you backed up only data files, you must
manually reinstall all your software before restoring your data files.
If your strategy is to back up your important data files, the procedure
can be simplified if you’ve stored all these files in one folder or its
subfolders.
Соседние файлы в предмете [НЕСОРТИРОВАННОЕ]